46 U.S.C. § 60303: Light money

A tax of 50 cents per ton, to be called “light money”, is imposed on a vessel not of the United States at each entry in a port of the United States. This tax shall be imposed and collected under the same regulations that apply to tonnage taxes. the vessel is carrying a regular document issued by a customhouse of the United States proving the vessel to be owned only by citizens of the United States; and the document contains the names of all the owners of the vessel; or part of the ownership has been transferred since the document was issued and, to the best of that individual’s knowledge and belief, the vessel is still owned only by citizens of the United States. an owner if one resides at the port of entry; or the master if an owner does not reside at the port of entry. is owned only by citizens of the United States; and after entering a port of the United States, becomes documented as a vessel of the United States before leaving that port.